A Williamson County jury sentenced a Brownsville man Thursday to life in prison in what authorities say was the largest methamphetamine drug bust in the county’s history.

The jury found William Silva, 27, guilty of possession of a controlled substance, a first-degree felony, on Thursday.

Silva was arrested in September after a sheriff’s deputy pulled him over on Interstate 35 near Jarrell, partly for weaving between lanes, according to testimony. The deputy arrested Silva for driving with a suspended license, and a police dog later detected narcotics, according to testimony.

Investigators found 42 pounds of methamphetamine inside a false compartment in the floor of the car, according an arrest affidavit.

That amount of methamphetamine is worth about $1.7 million, the sheriff’s office said.

According to a video of the traffic stop played in court, Silva told the officer he was on his way to Dallas from Brownsville to pick up an 18-wheeler and return home. His attorney, Daniel Gonzalez, said in court that Silva did not know the narcotics were in the vehicle. Silva must serve at least 15 years before he’s eligible for parole.